In electrical systems, plugs and sockets are typically used for providing electrical connectivity between devices. For purposes of cost effective mass manufacturing and flexibility in design, etc., plugs may be produced with common or similar structures, but may be used for different set-ups (for example, having different voltage rating configurations) of an electrical system. Likewise, sockets used for a particular set-up may also be structurally similar to sockets used for a different set-up.
Due to possible confusion caused by using commonly-structured or similarly-structured plugs and/or sockets, attempts have been made to ensure that a compatible plug is coupled to the correct socket. Such attempts include visual indications as exemplified in labeling and colour coding.
For example, relay plugs or plug-in relays currently available in the market have indications of voltage rating configurations printed on their housings, or have coloured pushbuttons installed thereon for visual indications on the different types of the relay plugs or plug-in relays. However, no corresponding indications are provided on the relay sockets receiving these relays. A relay socket, unlike a relay plug or a plug-in relay, typically does not carry any permanent indications of its voltage rating configuration because the relay socket is used for connecting to different set-ups for the controlling circuit and/or the controlled circuit and would therefore be subject to a voltage rating configuration that is dependent on each set-up.
The absence of any indication on the relay socket on the specific voltage rating configurations may prove difficult for users to easily, quickly and accurately identify the matching relay plug or plug-in relay for the specific relay socket. As a result, a high possibility of relay plug and socket mismatch exists. An incompatible relay plug or plug-in relay connected to an incorrect relay socket may lead to adverse consequences such as circuit malfunction or overloading which may cause the misoperation of the relay and/or eventually, to the failure of the circuits in the electrical system. Thus, it is important that the relay is of an appropriate voltage rating configuration for use in a set-up of the controlling circuit and the controlled circuit.
Providing visual indications and coloured pushbuttons for labelling the relay plugs to their specific voltage configuration is also not adequately effective in preventing or at substantially reducing the likelihood of a relay socket and relay plug or plug-in relay mismatch since oversight may still occur frequently.
Further, preparation or initialization of visual indications and colour pushbuttons may be cumbersome and time-consuming in that users, especially new users, may be unfamiliar with which indications are meant for which set-ups and may have to refer to guidelines or manuals in order for them to confirm how to proceed with the preparation or initialization of the indications.
In view of the above, there is a need to provide a socket, a plug, and a plug and socket assembly that address or at least ameliorate the above drawbacks, and improve usability.